When a spark ignition type internal combustion engine starts through cranking, it is desirable that an engine rotation speed be controlled to early increase to a target idle rotation speed by suppressing excessive increase in the engine rotation speed after complete combustion in order to suppress fuel consumption and obtain a desirable exhaust gas composition.
JP 2007-278073A, published by Japan Patent Office in 2007, discloses engine control for this purpose. Specifically, this control includes control of an intake throttle opening of an internal combustion engine, control of a fuel injection amount, and control of an ignition timing of injected fuel.
According to this prior art, increase of hydrocarbons (HC) in the exhaust gas is prevented by suppressing an excessive increase in the engine rotation speed generated after the engine rotation speed reaches a target idle rotation speed while controlling an air-fuel ratio to a stoichiometric air-fuel ratio.